Biaxially oriented polypropylene (BOPP) film is an important part of capacitor. The key parameters (ash content, isotacticity, molecular weight, melt flow rate, isotactic sequence length) of polypropylene resin used as raw materials for BOPP films and their influence rules were summarized in this paper. At the same time, the existing production technology of BOPP capacitor film was summarized, and the methods to improve the performance of BOPP film were further reviewed. Finally, it is proposed that the future development of BOPP films for capacitors will focus on the ultra-low ash resin raw materials and heat resistant films.

In this paper, the characteristics of high-frequency copper clad laminates were summarized, the dielectric properties of their base resins were compared, and the research progresses of hydrocarbon resin (PCH) high-frequency copper clad laminates were mainly introduced. By summarizing the current researches on hydrocarbon resin based high-frequency copper clad laminates, the existing problems were pointed out, and their future development trends were prospected.

A series of resins with ≥30% of solid content and about 4 000 mPa·s of viscosity and their polyimide films were prepared by introducing flexible 4,4′-oxobisphthalic anhydride (ODPA) or twisted non-coplanar structure 3,3′,4,4′-biphenyltetracarboxylic acid dianhydride (BPDA) into the molecular structure of homophthalic tetracarboxylic acid dianhydride-4,4′-diaminodiphenyl ether (PMDA-ODA), and capped with a capping agent. The properties of the films were characterized by tensile testing machine, breakdown voltage tester, TMA, DMA, TGA, and cross-cut tester. The results show that when the solid content of the semi-rigid structure PMDA-ODA resin increases to 30% and the viscosity reduces to about 4 000 mPa·s, the film could not be formed due to the low molecular weight, and the PI film with good electromechanical properties can be prepared through introducing flexible monomer to improve the the polymer flexibility and using norbornene diacetic anhydride (NA) for capping. When continuing to increase the resin solid content and increase the proportion of flexible monomers, the electromechanical properties, heat resistance, ahd the adhesion on the copper sheet of the film decrease. The films with 30% of solid content, about 4 000 mPa·s of viscosity, 30% mole fraction of ODPA, and end-capped with NA show better electromechanical properties, heat resistance, and adhesion, which can be used as a impregnating varnish for insulation protection on the surface of substrate.

Epoxy resin and its composite materials play a major insulation role in electrical apparatus due to their excellent thermodynamic and electrical insulating properties. With the gradual development of electrical apparatus towards high voltage and high power, as well as the continuous rise of voltage levels, the performance requirements for epoxy insulating materials inside electrical apparatus are increasingly increasing. This paper focused on epoxy resin insulating materials for high-voltage electrical apparatus, and reviewed the current research and application progress from three aspects: formulation composition, curing process, and performance improvement of insulation systems. It was aimed to establish the relationship between the composition, structure, and macroscopic properties of epoxy insulation systems, provide suggestions and prospects for the development direction of domestic epoxy resin insulating materials in the future, and accelerate the localization development of epoxy resin materials for high-voltage insulation.

In this paper, the basic research and application progress of high temperature resistant epoxy molding compound (EMC) at home and abroad in recent years were reviewed. The property requirements of advanced power electronics on the molding compound, the high temperature degradation mechanism of traditional EMC, the relationship between structure and thermal stability of EMC, and the modification pathways for improving the thermal stability of EMC were presented. Especially, the development status of multi-aromatic ring (MAR) and naphthalene-containing EMC were reviewed. At last, the future development trends of high temperature resistant EMC for power electronic packaging were prospected.

In this paper, the research progress on new eco-friendly insulating gases at home and abroad was reviewed, and the international mainstream promotion of perfluoroisobutyronitrile (C₄F₇N) gas and its application in electrical equipment were expounded emphatically. The gap and surface insulation characteristics of C₄F₇N gas mixture were summarized, and the design criteria of the related equipment insulation was proposed. The decomposition characteristics and gas-solid compatibility evaluation indices of C₄F₇N gas mixture under different operating conditions were analyzed. Additionally, the research progress on arc-quenching performance of C₄F₇N and its gas mixture and the development and application of a series of eco-friendly equipment were introduced, so as to provide a theoretical reference for the environmental protection upgrade of SF₆ electrical equipment in the current stage. Meanwhile, it was noted that the research and development efforts on new eco-friendly insulating gases with superior performance were still ongoing at home and abroad, which can provide technical support for the construction of a green and low-carbon power grid.

The frequent faults caused by buffer layer defects in high-voltage cross-linked polyethylene cables have seriously threatened the safe operation of power system. In this paper, the basic structure and function of buffer layers was introduced at first, and the relevant research on buffer layer failure at home and abroad were summarized. Secondly, the main reason of buffer layer defects was analyzed through electric field simulation from the material characteristic and internal structure of buffer layers, and the insulating properties and physicochemical characteristics of the white powder in buffer layer were summarized to propose its formation mechanism. Finally, the detection methods of buffer layer defects were summarized, it is proposed to use computer tomography technology to detect cable buffer layer defects to make up for the shortcomings of existing detection methods, and it is recommended to optimize the materials or structures of aluminum sheaths and buffer layers to prevent the generation of buffer layer defects.

This review mainly discusses the insulating materials adapted in chip packaging process from the perspective of the application of current silicon-based and next-generation silicone carbide (SiC) and other wide-bandgap semiconductor in power electronics packing, and prospects its future research trends towards requirements of high thermal conductivity and high temperature resistance.

In this paper, the performance and characteristics of low smoke halogen-free flame retardant cable material was reviewed. The advantage and disadvantage of ethylene-vinyl acetate copolymer (EVA) as the base material was introduced.The types and flame retardant mechanism of halogen-free flame retardant were reviewed. Finally, the development direction of low smoke halogen-free flame retardant cable material was prospected.

Photosensitive polyimide (PSPI) is widely used in electronics, microelectronics, optical display, and other fields. Foreign companies attach great importance to the patent protection of PSPI material formulas and applications. In this paper, the PSPI patents applied by Toray Industries Inc. in China were taken into research, and the changes in the number of patent applications, legal status, technical subject distribution, and other key information were analyzed in detail. Through combining with Toray's representative PSPI products and their applications, the technical development, patent protection strategy, key points of patent technology of Toray were clarified. Based on the above analysis, the technology development trends and application direction of PSPI materials were explored and presented.